more explicit check of Java executable -- relevant for Linux x86/x86_64 mismatch and absence on Mac OS Lion;
#!/usr/bin/env bash
#
# Author: Makarius
#
# DESCRIPTION: invoke Scala compiler within the Isabelle environment
[ -z "$SCALA_HOME" ] && { echo "Unknown SCALA_HOME -- Scala unavailable"; exit 2; }
[ -e "$ISABELLE_HOME/Admin/build" ] && { "$ISABELLE_HOME/Admin/build" jars || exit $?; }
CLASSPATH="$(jvmpath "$CLASSPATH")"
exec "$SCALA_HOME/bin/scalac" -Dfile.encoding=UTF-8 \
"-Djava.ext.dirs=$("$ISABELLE_HOME/lib/scripts/java_ext_dirs")" "$@"